An inquest has opened into the death of a security worker from Leamington Spa who was shot dead with a colleague and their interpreters while working for the United Nations in Afghanistan.

Former Royal Marine Leo Thomas Ryan, 35, was found dead on May 5 after being killed along with fellow Briton Timothy Rogers, the hearing was told.

Warwickshire Coroner Michael Coker revealed that the Surrey Coroner was holding a separate inquiry to establish the circumstances surrounding the death of Mr Rogers.

A friend of Mr Ryan, Ralph Gleeson, told the court that the Portsmouth-born soldier had lived at his home in Waverley Road, Leamington Spa, on occasions when he returned to the UK.

The witness said Mr Ryan, who was "estranged" from his parents, had served with the Marines before completing a business studies degree at the University of Liverpool and taking up work as an accountant.

The inquest was told that Mr Ryan accepted a six-month contract with the Army to work in Afghanistan last October, but he did not complete the term and returned to the war-torn state in December to work for a private company, Global Risk Strategies.

Mr Gleeson, who identified his friend's body when it was returned to Britain, said: "He was working for the United Nations as security for them.

"I last spoke to him on May 1 (on the telephone) as he was just going for a third operation in the hills."

Adjourning the inquest to a date to be fixed, the coroner said the exact circumstances of the fatal incident may never be known.

"In the circumstances, I can't take the matter any further at this stage," Mr Coker said.

"Obviously I shall be making inquiries of the Foreign and Commonwealth Office in the usual manner to obtain such information as is possible from Afghanistan because I have a duty to carry out an inquiry.

"Of course there will be no witnesses here who may have cogent evidence. They were just found by the roadside, and how that came about may be very difficult to ascertain in somewhere like Afghanistan."